Capital Gains Tax on Financial Assets in Belgium: 2026 Guide

Key takeaways

• The 10% capital gains tax on financial assets has applied since 1 January 2026, under the Law of 6 April 2026 (Official Gazette, 21 April 2026).
• An annual exemption of €10,000 per individual reduces the taxable base; unused exemptions accumulate up to a maximum of €15,000.
• Three regimes coexist: 10% for assets held in an ordinary private capacity, a progressive scale for substantial participations (20% or more), and 33% for disposals to controlled entities.
• Since 1 June 2026, withholding at source by the financial intermediary is the default mechanism; gains from 1 January to 31 May 2026 may be voluntarily paid before 31 August 2026.
• Unrealised gains prior to 31 December 2025 are fully exempt through the reference value mechanism.

The capital gains tax on financial assets is one of the most significant tax reforms introduced by the Arizona government in Belgium. Adopted on 3 April 2026 by the Chamber and promulgated on 6 April 2026 (published in the Belgian Official Gazette on 21 April 2026), it applies retroactively to gains realised since 1 January 2026. Whether you are a private individual, a private investor, self-employed, or a representative of a non-profit association, this guide explains the precise scope, the three tax regimes, the exemptions, and the practical deadlines still open in July 2026.

Which assets fall within the scope of the tax

The law organises the assets concerned into four categories. Each covers distinct products, and the exclusions are just as precisely defined as the scope.

Categories of financial assets concerned

• Shares, participations and equity interests

  Listed or unlisted, held privately in a proportion below 20% of the company (above that threshold, see the substantial participation regime).

• Bonds and debt securities

  Sovereign, corporate or structured bonds, as well as fixed-income instruments issued in Belgium or abroad.

• ETFs, options, warrants and derivative instruments

  Exchange-traded funds, option contracts, warrants, futures, CFDs and emission rights.

• Crypto-assets

  Cryptocurrencies, stablecoins, utility tokens and certain NFTs used for payment or investment purposes, within the meaning of EU Regulation MiCA (EU 2023/1114).

• Life insurance and capitalisation contracts

  Branches 21 (guaranteed-rate), 22, 23 (unit-linked), 26 and 44, as well as their foreign equivalents. Excluded: group insurance (pillar 2) and pension savings plans (pillar 3).

• Currencies and investment-grade precious metals

  Foreign exchange gains on foreign currencies and investment gold (995/1000 purity or 24 carats).

Real estate, artworks, jewellery, antiques and pillar 2 and 3 pension plans are explicitly excluded. Gains generated in a habitual professional or speculative context continue to be taxed under the pre-existing rules of the Code of Income Taxes 1992 (CIR 92), separately from this tax.

Three regimes depending on the nature of the disposal

The law does not create a single rate: it distinguishes three regimes depending on the relationship between the seller and the company whose securities are being sold.

	Applicable rate	Main conditions
General regime	10% (flat rate)	Financial assets held privately, participation below 20%
Substantial participation (≥ 20%)	Progressive scale 0% to 10%	Holding of 20% or more of rights in a company, exemption of €1,000,000 over 5 years
Internal disposal	33%	Sale to an entity controlled by the seller or their relatives up to the 2nd degree, no exemption

The 10% regime applies to the vast majority of individuals and self-employed persons managing a private portfolio. The substantial participation regime targets business owners selling their own company: the €1 million exemption over five years is designed not to penalise the sale of a family SME. The 33% rate for internal disposals serves an anti-avoidance purpose: it prevents circumventing the tax by selling assets to a company one controls.

Annual exemption and partial carry-forward

Under the general regime (10%), the taxable base is reduced by a personal exemption.

The exemption applies to the annual net balance: total gains minus losses realised in the same year and under the same regime. Transaction costs (brokerage fees, custody charges) are not deductible. A net negative balance after within-year loss offsetting is extinguished at the close of the tax year, with no carry-forward available.

Married couples and legal cohabitants each receive their own €10,000 exemption, giving €20,000 combined, and up to €30,000 if both spouses have accumulated the full carry-forward.

Historical gains: the reference value mechanism of 31 December 2025

Financial assets held before 1 January 2026 benefit from a key transitional mechanism: the value on 31 December 2025 replaces the historical acquisition price as the fiscal reference cost. Gains accumulated before that date are therefore entirely exempt.

In practice, if you acquired shares in 2019 and dispose of them in 2026, only the appreciation realised since 1 January 2026 enters the taxable base. The portion corresponding to appreciation between 2019 and 31 December 2025 remains exempt.

A special case applies to assets whose value on 31 December 2025 was below the acquisition price ("underwater" assets): the taxpayer may, until 31 December 2030, elect to use the original acquisition price instead of the reference value, provided they can prove it and declare it in their personal income tax return.

For new Belgian tax residents arriving in Belgium after 1 January 2026, the reference value is the market value on the date Belgian tax residence is established: no tax applies to gains accumulated before arrival.

Declaration and collection: opt-in or opt-out

Tax collection is based on a two-option mechanism governed by the Royal Decree of 18 May 2026.

1. 1

   1 January 2026: tax enters into force

   Past

   Gains realised from this date are taxable. During the transitional period (January to May 2026), no withholding at source was levied by financial intermediaries, as the published legal basis was not yet in place.

2. 2

   31 May 2026: deadline to opt out for 2026

   Past

   Taxpayers wishing to manage their own declaration (opt-out) had to notify their Belgian bank or broker before this date. After this deadline, the default mechanism (opt-in) applies automatically for the rest of the year.

3. 3

   1 June 2026: withholding at source begins (opt-in by default)

   In force

   Belgian financial intermediaries automatically withhold 10% on each gain realised. The withholding has a liberating effect: no additional declaration in the personal income tax return is required for those gains. The taxpayer may nonetheless file a return to recover any excess withheld (exemption, losses).

4. 4

   31 August 2026: voluntary payment for the transition period

   Upcoming

   Gains realised between 1 January and 31 May 2026 (the period without automatic withholding) may be voluntarily paid before this date, and the opt-out for gains from 1 June to 1 September 2026 may still be exercised.

5. 5

   1 March 2027: intermediaries' report to the tax authority

   Upcoming

   For opt-out accounts, Belgian financial intermediaries electronically transmit transaction data to the SPF Finances. Opt-out taxpayers must declare their net capital gains in their personal income tax return.

Withholding at source (opt-in) preserves investor anonymity: the intermediary does not share transaction details with the tax authority. Under opt-out, the intermediary is required to report data to the administration. Crypto-assets held in non-custodial wallets and assets with foreign brokers without opt-in are never subject to automatic withholding: they must always be declared in the personal income tax return.

If you are considering creating an SRL in Belgium, the choice between operating as a self-employed individual and setting up a company directly affects the regime applicable to your investment income: a company does not benefit from the €10,000 exemption, but intra-portfolio gains within the company fall under corporate income tax (ISoc). Our article on SRL or SA in Belgium analyses the selection criteria.

What structure best fits your tax situation?

The choice between operating as a self-employed individual and incorporating a company directly impacts your capital gains tax burden. Monsiegesocial guides you through company formation and registered office services in Belgium.

Discover our servicesForm my company

Practical examples: calculating the tax under the general regime

A few concrete examples to gauge the real impact on a private portfolio.

Case 1: investor with an all-post-2026 equity portfolio. In 2026, you realise gains of €18,000 on shares acquired since 1 January 2026, and losses of €3,000 on an ETF. You have no carry-forward exemption. Net gain: €15,000. After the annual exemption of €10,000, the taxable base is €5,000. Tax due: €500. (Note: brokerage fees are not deductible.)

Case 2: investor with historical assets. You hold shares purchased in 2018 whose value has risen by €40,000 since purchase, of which €8,000 since 1 January 2026 (post-reference gain). Only those €8,000 are taxable. With your €10,000 exemption (no carry-forward, first disposal), the taxable base is nil. Tax due: €0. The unused exemption generates a carry-forward of €1,000 for 2027.

Case 3: business owner with a 25% participation in their SRL (substantial participation regime). They dispose of their participation and realise a gain of €600,000. Since this amount is below the €1,000,000 exemption over five years, the entire gain is exempt. Tax due: €0. If the sale had generated €1,400,000, the €400,000 tranche above the million would be taxed at 1.25%, giving €5,000.

For an understanding of how this tax interacts with corporate income tax on your business revenues, our guide on corporate income tax in Belgium covers ISoc rates, the definitively taxed income (RDT/DBI) regime, and the construction of the taxable base.

Further reading

• Corporate income tax in Belgium: rates, calculation and SME reduced rate: understanding ISoc applicable to companies, as a complement to personal capital gains taxation.
• SRL or SA: which legal form to choose in Belgium?: the choice of structure determines how your investment income and capital gains are treated for tax purposes.
• SPF Finances: capital gains tax on financial assets: the official reference for declarations, payment procedures and the tax authority's FAQ.